view src/mail/ngx_mail_parse.c @ 7418:ce5e87e98772 stable-1.14

SSL: logging level of "no suitable key share". The "no suitable key share" errors are reported by OpenSSL 1.1.1 when using TLSv1.3 if there are no shared groups (that is, elliptic curves). In particular, it is easy enough to trigger by using only a single curve in ssl_ecdh_curve: ssl_ecdh_curve secp384r1; and using a different curve in the client: openssl s_client -connect 127.0.0.1:443 -curves prime256v1 On the client side it is seen as "sslv3 alert handshake failure", "SSL alert number 40": 0:error:14094410:SSL routines:ssl3_read_bytes:sslv3 alert handshake failure:ssl/record/rec_layer_s3.c:1528:SSL alert number 40 It can be also triggered with default ssl_ecdh_curve by using a curve which is not in the default list (X25519, prime256v1, X448, secp521r1, secp384r1): openssl s_client -connect 127.0.0.1:8443 -curves brainpoolP512r1 Given that many clients hardcode prime256v1, these errors might become a common problem with TLSv1.3 if ssl_ecdh_curve is redefined. Previously this resulted in not using ECDH with such clients, but with TLSv1.3 it is no longer possible and will result in a handshake failure. The SSL_R_NO_SHARED_GROUP error is what BoringSSL returns in the same situation. Seen at: https://serverfault.com/questions/932102/nginx-ssl-handshake-error-no-suitable-key-share
author Maxim Dounin <mdounin@mdounin.ru>
date Tue, 25 Sep 2018 13:59:53 +0300
parents bcb107bb89cd
children 6a81d96d3733
line wrap: on
line source


/*
 * Copyright (C) Igor Sysoev
 * Copyright (C) Nginx, Inc.
 */


#include <ngx_config.h>
#include <ngx_core.h>
#include <ngx_event.h>
#include <ngx_mail.h>
#include <ngx_mail_pop3_module.h>
#include <ngx_mail_imap_module.h>
#include <ngx_mail_smtp_module.h>


ngx_int_t
ngx_mail_pop3_parse_command(ngx_mail_session_t *s)
{
    u_char      ch, *p, *c, c0, c1, c2, c3;
    ngx_str_t  *arg;
    enum {
        sw_start = 0,
        sw_spaces_before_argument,
        sw_argument,
        sw_almost_done
    } state;

    state = s->state;

    for (p = s->buffer->pos; p < s->buffer->last; p++) {
        ch = *p;

        switch (state) {

        /* POP3 command */
        case sw_start:
            if (ch == ' ' || ch == CR || ch == LF) {
                c = s->buffer->start;

                if (p - c == 4) {

                    c0 = ngx_toupper(c[0]);
                    c1 = ngx_toupper(c[1]);
                    c2 = ngx_toupper(c[2]);
                    c3 = ngx_toupper(c[3]);

                    if (c0 == 'U' && c1 == 'S' && c2 == 'E' && c3 == 'R')
                    {
                        s->command = NGX_POP3_USER;

                    } else if (c0 == 'P' && c1 == 'A' && c2 == 'S' && c3 == 'S')
                    {
                        s->command = NGX_POP3_PASS;

                    } else if (c0 == 'A' && c1 == 'P' && c2 == 'O' && c3 == 'P')
                    {
                        s->command = NGX_POP3_APOP;

                    } else if (c0 == 'Q' && c1 == 'U' && c2 == 'I' && c3 == 'T')
                    {
                        s->command = NGX_POP3_QUIT;

                    } else if (c0 == 'C' && c1 == 'A' && c2 == 'P' && c3 == 'A')
                    {
                        s->command = NGX_POP3_CAPA;

                    } else if (c0 == 'A' && c1 == 'U' && c2 == 'T' && c3 == 'H')
                    {
                        s->command = NGX_POP3_AUTH;

                    } else if (c0 == 'N' && c1 == 'O' && c2 == 'O' && c3 == 'P')
                    {
                        s->command = NGX_POP3_NOOP;
#if (NGX_MAIL_SSL)
                    } else if (c0 == 'S' && c1 == 'T' && c2 == 'L' && c3 == 'S')
                    {
                        s->command = NGX_POP3_STLS;
#endif
                    } else {
                        goto invalid;
                    }

                } else {
                    goto invalid;
                }

                switch (ch) {
                case ' ':
                    state = sw_spaces_before_argument;
                    break;
                case CR:
                    state = sw_almost_done;
                    break;
                case LF:
                    goto done;
                }
                break;
            }

            if ((ch < 'A' || ch > 'Z') && (ch < 'a' || ch > 'z')) {
                goto invalid;
            }

            break;

        case sw_spaces_before_argument:
            switch (ch) {
            case ' ':
                break;
            case CR:
                state = sw_almost_done;
                s->arg_end = p;
                break;
            case LF:
                s->arg_end = p;
                goto done;
            default:
                if (s->args.nelts <= 2) {
                    state = sw_argument;
                    s->arg_start = p;
                    break;
                }
                goto invalid;
            }
            break;

        case sw_argument:
            switch (ch) {

            case ' ':

                /*
                 * the space should be considered as part of the at username
                 * or password, but not of argument in other commands
                 */

                if (s->command == NGX_POP3_USER
                    || s->command == NGX_POP3_PASS)
                {
                    break;
                }

                /* fall through */

            case CR:
            case LF:
                arg = ngx_array_push(&s->args);
                if (arg == NULL) {
                    return NGX_ERROR;
                }
                arg->len = p - s->arg_start;
                arg->data = s->arg_start;
                s->arg_start = NULL;

                switch (ch) {
                case ' ':
                    state = sw_spaces_before_argument;
                    break;
                case CR:
                    state = sw_almost_done;
                    break;
                case LF:
                    goto done;
                }
                break;

            default:
                break;
            }
            break;

        case sw_almost_done:
            switch (ch) {
            case LF:
                goto done;
            default:
                goto invalid;
            }
        }
    }

    s->buffer->pos = p;
    s->state = state;

    return NGX_AGAIN;

done:

    s->buffer->pos = p + 1;

    if (s->arg_start) {
        arg = ngx_array_push(&s->args);
        if (arg == NULL) {
            return NGX_ERROR;
        }
        arg->len = s->arg_end - s->arg_start;
        arg->data = s->arg_start;
        s->arg_start = NULL;
    }

    s->state = (s->command != NGX_POP3_AUTH) ? sw_start : sw_argument;

    return NGX_OK;

invalid:

    s->state = sw_start;
    s->arg_start = NULL;

    return NGX_MAIL_PARSE_INVALID_COMMAND;
}


ngx_int_t
ngx_mail_imap_parse_command(ngx_mail_session_t *s)
{
    u_char      ch, *p, *c;
    ngx_str_t  *arg;
    enum {
        sw_start = 0,
        sw_spaces_before_command,
        sw_command,
        sw_spaces_before_argument,
        sw_argument,
        sw_backslash,
        sw_literal,
        sw_no_sync_literal_argument,
        sw_start_literal_argument,
        sw_literal_argument,
        sw_end_literal_argument,
        sw_almost_done
    } state;

    state = s->state;

    for (p = s->buffer->pos; p < s->buffer->last; p++) {
        ch = *p;

        switch (state) {

        /* IMAP tag */
        case sw_start:
            switch (ch) {
            case ' ':
                s->tag.len = p - s->buffer->start + 1;
                s->tag.data = s->buffer->start;
                state = sw_spaces_before_command;
                break;
            case CR:
                s->state = sw_start;
                return NGX_MAIL_PARSE_INVALID_COMMAND;
            case LF:
                s->state = sw_start;
                return NGX_MAIL_PARSE_INVALID_COMMAND;
            }
            break;

        case sw_spaces_before_command:
            switch (ch) {
            case ' ':
                break;
            case CR:
                s->state = sw_start;
                return NGX_MAIL_PARSE_INVALID_COMMAND;
            case LF:
                s->state = sw_start;
                return NGX_MAIL_PARSE_INVALID_COMMAND;
            default:
                s->cmd_start = p;
                state = sw_command;
                break;
            }
            break;

        case sw_command:
            if (ch == ' ' || ch == CR || ch == LF) {

                c = s->cmd_start;

                switch (p - c) {

                case 4:
                    if ((c[0] == 'N' || c[0] == 'n')
                        && (c[1] == 'O'|| c[1] == 'o')
                        && (c[2] == 'O'|| c[2] == 'o')
                        && (c[3] == 'P'|| c[3] == 'p'))
                    {
                        s->command = NGX_IMAP_NOOP;

                    } else {
                        goto invalid;
                    }
                    break;

                case 5:
                    if ((c[0] == 'L'|| c[0] == 'l')
                        && (c[1] == 'O'|| c[1] == 'o')
                        && (c[2] == 'G'|| c[2] == 'g')
                        && (c[3] == 'I'|| c[3] == 'i')
                        && (c[4] == 'N'|| c[4] == 'n'))
                    {
                        s->command = NGX_IMAP_LOGIN;

                    } else {
                        goto invalid;
                    }
                    break;

                case 6:
                    if ((c[0] == 'L'|| c[0] == 'l')
                        && (c[1] == 'O'|| c[1] == 'o')
                        && (c[2] == 'G'|| c[2] == 'g')
                        && (c[3] == 'O'|| c[3] == 'o')
                        && (c[4] == 'U'|| c[4] == 'u')
                        && (c[5] == 'T'|| c[5] == 't'))
                    {
                        s->command = NGX_IMAP_LOGOUT;

                    } else {
                        goto invalid;
                    }
                    break;

#if (NGX_MAIL_SSL)
                case 8:
                    if ((c[0] == 'S'|| c[0] == 's')
                        && (c[1] == 'T'|| c[1] == 't')
                        && (c[2] == 'A'|| c[2] == 'a')
                        && (c[3] == 'R'|| c[3] == 'r')
                        && (c[4] == 'T'|| c[4] == 't')
                        && (c[5] == 'T'|| c[5] == 't')
                        && (c[6] == 'L'|| c[6] == 'l')
                        && (c[7] == 'S'|| c[7] == 's'))
                    {
                        s->command = NGX_IMAP_STARTTLS;

                    } else {
                        goto invalid;
                    }
                    break;
#endif

                case 10:
                    if ((c[0] == 'C'|| c[0] == 'c')
                        && (c[1] == 'A'|| c[1] == 'a')
                        && (c[2] == 'P'|| c[2] == 'p')
                        && (c[3] == 'A'|| c[3] == 'a')
                        && (c[4] == 'B'|| c[4] == 'b')
                        && (c[5] == 'I'|| c[5] == 'i')
                        && (c[6] == 'L'|| c[6] == 'l')
                        && (c[7] == 'I'|| c[7] == 'i')
                        && (c[8] == 'T'|| c[8] == 't')
                        && (c[9] == 'Y'|| c[9] == 'y'))
                    {
                        s->command = NGX_IMAP_CAPABILITY;

                    } else {
                        goto invalid;
                    }
                    break;

                case 12:
                    if ((c[0] == 'A'|| c[0] == 'a')
                        && (c[1] == 'U'|| c[1] == 'u')
                        && (c[2] == 'T'|| c[2] == 't')
                        && (c[3] == 'H'|| c[3] == 'h')
                        && (c[4] == 'E'|| c[4] == 'e')
                        && (c[5] == 'N'|| c[5] == 'n')
                        && (c[6] == 'T'|| c[6] == 't')
                        && (c[7] == 'I'|| c[7] == 'i')
                        && (c[8] == 'C'|| c[8] == 'c')
                        && (c[9] == 'A'|| c[9] == 'a')
                        && (c[10] == 'T'|| c[10] == 't')
                        && (c[11] == 'E'|| c[11] == 'e'))
                    {
                        s->command = NGX_IMAP_AUTHENTICATE;

                    } else {
                        goto invalid;
                    }
                    break;

                default:
                    goto invalid;
                }

                switch (ch) {
                case ' ':
                    state = sw_spaces_before_argument;
                    break;
                case CR:
                    state = sw_almost_done;
                    break;
                case LF:
                    goto done;
                }
                break;
            }

            if ((ch < 'A' || ch > 'Z') && (ch < 'a' || ch > 'z')) {
                goto invalid;
            }

            break;

        case sw_spaces_before_argument:
            switch (ch) {
            case ' ':
                break;
            case CR:
                state = sw_almost_done;
                s->arg_end = p;
                break;
            case LF:
                s->arg_end = p;
                goto done;
            case '"':
                if (s->args.nelts <= 2) {
                    s->quoted = 1;
                    s->arg_start = p + 1;
                    state = sw_argument;
                    break;
                }
                goto invalid;
            case '{':
                if (s->args.nelts <= 2) {
                    state = sw_literal;
                    break;
                }
                goto invalid;
            default:
                if (s->args.nelts <= 2) {
                    s->arg_start = p;
                    state = sw_argument;
                    break;
                }
                goto invalid;
            }
            break;

        case sw_argument:
            if (ch == ' ' && s->quoted) {
                break;
            }

            switch (ch) {
            case '"':
                if (!s->quoted) {
                    break;
                }
                s->quoted = 0;
                /* fall through */
            case ' ':
            case CR:
            case LF:
                arg = ngx_array_push(&s->args);
                if (arg == NULL) {
                    return NGX_ERROR;
                }
                arg->len = p - s->arg_start;
                arg->data = s->arg_start;
                s->arg_start = NULL;

                switch (ch) {
                case '"':
                case ' ':
                    state = sw_spaces_before_argument;
                    break;
                case CR:
                    state = sw_almost_done;
                    break;
                case LF:
                    goto done;
                }
                break;
            case '\\':
                if (s->quoted) {
                    s->backslash = 1;
                    state = sw_backslash;
                }
                break;
            }
            break;

        case sw_backslash:
            switch (ch) {
            case CR:
            case LF:
                goto invalid;
            default:
                state = sw_argument;
            }
            break;

        case sw_literal:
            if (ch >= '0' && ch <= '9') {
                s->literal_len = s->literal_len * 10 + (ch - '0');
                break;
            }
            if (ch == '}') {
                state = sw_start_literal_argument;
                break;
            }
            if (ch == '+') {
                state = sw_no_sync_literal_argument;
                break;
            }
            goto invalid;

        case sw_no_sync_literal_argument:
            if (ch == '}') {
                s->no_sync_literal = 1;
                state = sw_start_literal_argument;
                break;
            }
            goto invalid;

        case sw_start_literal_argument:
            switch (ch) {
            case CR:
                break;
            case LF:
                s->buffer->pos = p + 1;
                s->arg_start = p + 1;
                if (s->no_sync_literal == 0) {
                    s->state = sw_literal_argument;
                    return NGX_IMAP_NEXT;
                }
                state = sw_literal_argument;
                s->no_sync_literal = 0;
                break;
            default:
                goto invalid;
            }
            break;

        case sw_literal_argument:
            if (s->literal_len && --s->literal_len) {
                break;
            }

            arg = ngx_array_push(&s->args);
            if (arg == NULL) {
                return NGX_ERROR;
            }
            arg->len = p + 1 - s->arg_start;
            arg->data = s->arg_start;
            s->arg_start = NULL;
            state = sw_end_literal_argument;

            break;

        case sw_end_literal_argument:
            switch (ch) {
            case '{':
                if (s->args.nelts <= 2) {
                    state = sw_literal;
                    break;
                }
                goto invalid;
            case CR:
                state = sw_almost_done;
                break;
            case LF:
                goto done;
            default:
                state = sw_spaces_before_argument;
                break;
            }
            break;

        case sw_almost_done:
            switch (ch) {
            case LF:
                goto done;
            default:
                goto invalid;
            }
        }
    }

    s->buffer->pos = p;
    s->state = state;

    return NGX_AGAIN;

done:

    s->buffer->pos = p + 1;

    if (s->arg_start) {
        arg = ngx_array_push(&s->args);
        if (arg == NULL) {
            return NGX_ERROR;
        }
        arg->len = s->arg_end - s->arg_start;
        arg->data = s->arg_start;

        s->arg_start = NULL;
        s->cmd_start = NULL;
        s->quoted = 0;
        s->no_sync_literal = 0;
        s->literal_len = 0;
    }

    s->state = (s->command != NGX_IMAP_AUTHENTICATE) ? sw_start : sw_argument;

    return NGX_OK;

invalid:

    s->state = sw_start;
    s->quoted = 0;
    s->no_sync_literal = 0;
    s->literal_len = 0;

    return NGX_MAIL_PARSE_INVALID_COMMAND;
}


ngx_int_t
ngx_mail_smtp_parse_command(ngx_mail_session_t *s)
{
    u_char      ch, *p, *c, c0, c1, c2, c3;
    ngx_str_t  *arg;
    enum {
        sw_start = 0,
        sw_command,
        sw_invalid,
        sw_spaces_before_argument,
        sw_argument,
        sw_almost_done
    } state;

    state = s->state;

    for (p = s->buffer->pos; p < s->buffer->last; p++) {
        ch = *p;

        switch (state) {

        /* SMTP command */
        case sw_start:
            s->cmd_start = p;
            state = sw_command;

            /* fall through */

        case sw_command:
            if (ch == ' ' || ch == CR || ch == LF) {
                c = s->cmd_start;

                if (p - c == 4) {

                    c0 = ngx_toupper(c[0]);
                    c1 = ngx_toupper(c[1]);
                    c2 = ngx_toupper(c[2]);
                    c3 = ngx_toupper(c[3]);

                    if (c0 == 'H' && c1 == 'E' && c2 == 'L' && c3 == 'O')
                    {
                        s->command = NGX_SMTP_HELO;

                    } else if (c0 == 'E' && c1 == 'H' && c2 == 'L' && c3 == 'O')
                    {
                        s->command = NGX_SMTP_EHLO;

                    } else if (c0 == 'Q' && c1 == 'U' && c2 == 'I' && c3 == 'T')
                    {
                        s->command = NGX_SMTP_QUIT;

                    } else if (c0 == 'A' && c1 == 'U' && c2 == 'T' && c3 == 'H')
                    {
                        s->command = NGX_SMTP_AUTH;

                    } else if (c0 == 'N' && c1 == 'O' && c2 == 'O' && c3 == 'P')
                    {
                        s->command = NGX_SMTP_NOOP;

                    } else if (c0 == 'M' && c1 == 'A' && c2 == 'I' && c3 == 'L')
                    {
                        s->command = NGX_SMTP_MAIL;

                    } else if (c0 == 'R' && c1 == 'S' && c2 == 'E' && c3 == 'T')
                    {
                        s->command = NGX_SMTP_RSET;

                    } else if (c0 == 'R' && c1 == 'C' && c2 == 'P' && c3 == 'T')
                    {
                        s->command = NGX_SMTP_RCPT;

                    } else if (c0 == 'V' && c1 == 'R' && c2 == 'F' && c3 == 'Y')
                    {
                        s->command = NGX_SMTP_VRFY;

                    } else if (c0 == 'E' && c1 == 'X' && c2 == 'P' && c3 == 'N')
                    {
                        s->command = NGX_SMTP_EXPN;

                    } else if (c0 == 'H' && c1 == 'E' && c2 == 'L' && c3 == 'P')
                    {
                        s->command = NGX_SMTP_HELP;

                    } else {
                        goto invalid;
                    }
#if (NGX_MAIL_SSL)
                } else if (p - c == 8) {

                    if ((c[0] == 'S'|| c[0] == 's')
                        && (c[1] == 'T'|| c[1] == 't')
                        && (c[2] == 'A'|| c[2] == 'a')
                        && (c[3] == 'R'|| c[3] == 'r')
                        && (c[4] == 'T'|| c[4] == 't')
                        && (c[5] == 'T'|| c[5] == 't')
                        && (c[6] == 'L'|| c[6] == 'l')
                        && (c[7] == 'S'|| c[7] == 's'))
                    {
                        s->command = NGX_SMTP_STARTTLS;

                    } else {
                        goto invalid;
                    }
#endif
                } else {
                    goto invalid;
                }

                s->cmd.data = s->cmd_start;
                s->cmd.len = p - s->cmd_start;

                switch (ch) {
                case ' ':
                    state = sw_spaces_before_argument;
                    break;
                case CR:
                    state = sw_almost_done;
                    break;
                case LF:
                    goto done;
                }
                break;
            }

            if ((ch < 'A' || ch > 'Z') && (ch < 'a' || ch > 'z')) {
                goto invalid;
            }

            break;

        case sw_invalid:
            goto invalid;

        case sw_spaces_before_argument:
            switch (ch) {
            case ' ':
                break;
            case CR:
                state = sw_almost_done;
                s->arg_end = p;
                break;
            case LF:
                s->arg_end = p;
                goto done;
            default:
                if (s->args.nelts <= 10) {
                    state = sw_argument;
                    s->arg_start = p;
                    break;
                }
                goto invalid;
            }
            break;

        case sw_argument:
            switch (ch) {
            case ' ':
            case CR:
            case LF:
                arg = ngx_array_push(&s->args);
                if (arg == NULL) {
                    return NGX_ERROR;
                }
                arg->len = p - s->arg_start;
                arg->data = s->arg_start;
                s->arg_start = NULL;

                switch (ch) {
                case ' ':
                    state = sw_spaces_before_argument;
                    break;
                case CR:
                    state = sw_almost_done;
                    break;
                case LF:
                    goto done;
                }
                break;

            default:
                break;
            }
            break;

        case sw_almost_done:
            switch (ch) {
            case LF:
                goto done;
            default:
                goto invalid;
            }
        }
    }

    s->buffer->pos = p;
    s->state = state;

    return NGX_AGAIN;

done:

    s->buffer->pos = p + 1;

    if (s->arg_start) {
        arg = ngx_array_push(&s->args);
        if (arg == NULL) {
            return NGX_ERROR;
        }
        arg->len = s->arg_end - s->arg_start;
        arg->data = s->arg_start;
        s->arg_start = NULL;
    }

    s->state = (s->command != NGX_SMTP_AUTH) ? sw_start : sw_argument;

    return NGX_OK;

invalid:

    s->state = sw_invalid;
    s->arg_start = NULL;

    /* skip invalid command till LF */

    for (p = s->buffer->pos; p < s->buffer->last; p++) {
        if (*p == LF) {
            s->state = sw_start;
            p++;
            break;
        }
    }

    s->buffer->pos = p;

    return NGX_MAIL_PARSE_INVALID_COMMAND;
}


ngx_int_t
ngx_mail_auth_parse(ngx_mail_session_t *s, ngx_connection_t *c)
{
    ngx_str_t                 *arg;

#if (NGX_MAIL_SSL)
    if (ngx_mail_starttls_only(s, c)) {
        return NGX_MAIL_PARSE_INVALID_COMMAND;
    }
#endif

    if (s->args.nelts == 0) {
        return NGX_MAIL_PARSE_INVALID_COMMAND;
    }

    arg = s->args.elts;

    if (arg[0].len == 5) {

        if (ngx_strncasecmp(arg[0].data, (u_char *) "LOGIN", 5) == 0) {

            if (s->args.nelts == 1) {
                return NGX_MAIL_AUTH_LOGIN;
            }

            if (s->args.nelts == 2) {
                return NGX_MAIL_AUTH_LOGIN_USERNAME;
            }

            return NGX_MAIL_PARSE_INVALID_COMMAND;
        }

        if (ngx_strncasecmp(arg[0].data, (u_char *) "PLAIN", 5) == 0) {

            if (s->args.nelts == 1) {
                return NGX_MAIL_AUTH_PLAIN;
            }

            if (s->args.nelts == 2) {
                return ngx_mail_auth_plain(s, c, 1);
            }
        }

        return NGX_MAIL_PARSE_INVALID_COMMAND;
    }

    if (arg[0].len == 8) {

        if (ngx_strncasecmp(arg[0].data, (u_char *) "CRAM-MD5", 8) == 0) {

            if (s->args.nelts != 1) {
                return NGX_MAIL_PARSE_INVALID_COMMAND;
            }

            return NGX_MAIL_AUTH_CRAM_MD5;
        }

        if (ngx_strncasecmp(arg[0].data, (u_char *) "EXTERNAL", 8) == 0) {

            if (s->args.nelts == 1) {
                return NGX_MAIL_AUTH_EXTERNAL;
            }

            if (s->args.nelts == 2) {
                return ngx_mail_auth_external(s, c, 1);
            }
        }

        return NGX_MAIL_PARSE_INVALID_COMMAND;
    }

    return NGX_MAIL_PARSE_INVALID_COMMAND;
}